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NIELS BOHR Is Born
Niels Bohr was born on October 7, 1887 in Copenhagen, Denmark. His father, Christian Bohr, was a physiology professor and his mother, Ellen Adler Bohr, was a daughter of a wealthy Danish Jewish family. https://www.youtube.com/watch?v=1b9UKTbjj7I -
The Bohr-Van Leeuwen Theorem
While working on his PhD thesis he discovered the Bohr–van Leeuwen theorem. The importance of Bohr’s discovery is that classical physics does not allow for such things as paramagnetism, diamagnetism and ferromagnetism, and thus quantum physics is needed to explain these magnetic events. The Bohr–van Leeuwen theorem is useful in several applications including plasma physics. Electro-mechanics and electrical engineering also practically benefit from it. -
Bohr's Model
Bohr's paper on atomic structure, On the Constitution of Atoms and Molecules, is published and later becomes the basis of the "old quantum theory". The trilogy of articles published in The Philosophical Magazine in 1913, stated that electrons could only occupy particular orbits determined by the quantum of action and that electromagnetic radiation from an atom occurred only when an electron jumped to a lower-energy orbit. https://www.youtube.com/watch?v=S1LDJUu4nko -
Victoria University of Manchester, UK
Bohr held a lectureship in physics at Copenhagen University from 1913 to 1914 and went on to hold a similar position at Victoria University in Manchester from 1914 to 1916. He went back to Copenhagen University in 1916 to become a professor of theoretical physics, a position which he held for 46 years. -
Institute of Theoretical Physics
In April 1917, Bohr began a campaign to establish an Institute of Theoretical Physics. He gained the support of the Danish government and the Carlsberg Foundation, and sizeable contributions were also made by industry and private donors, many of them Jewish. Legislation establishing the Institute was passed in November 1918. https://www.youtube.com/watch?v=jpRQ-Y2U-Z4 -
Noble Prize
Bohr is awarded the Noble Prize in Physics for his services in the investigation of the structure of atoms and of the radiation emanating from them. In his 1913 trilogy, Bohr had sought to apply his theory to the understanding of the periodic table of elements. He improved upon that aspect of his work into the early 1920s, by which time he had developed an elaborate scheme building up the periodic table by adding electrons one after another to the atom according to his atomic model. -
BKS Theory
In 1924, Bohr, Kramers, and John C. Slater proposed the Bohr–Kramers–Slater theory (BKS). It was more a programme than a full physical theory, as the ideas it developed were not worked out quantitatively. BKS theory became the final attempt at understanding the interaction of matter and electromagnetic radiation on the basis of the old quantum theory, in which quantum phenomena were treated by imposing quantum restrictions on a classical wave description of the electromagnetic field. -
Copenhagen Interpretation
Niels Bohr and two others, devise the Copenhagen interpretation of quantum mechanics. By it, systems at atomic level don’t have definite properties prior to being measured. The act of measurement affects the system and causes it to select one of the various possible values after measurement. This feature is known as wavefunction collapse. The Copenhagen interpretation still provides a conceptual basis for quantum mechanics and remains among the most prominent interpretations of the theory. -
Complementarity Principle
In 1927, Niels Bohr formulated the principle of complementarity stated that the atomic level a physical phenomenon expresses itself differently depending on the experimental setup used to observe it. Thus, light appears sometimes as waves and sometimes as particles. Examples of complementary properties thus include wave-particle duality. Complementarity formed the basis of early quantum theory and is both a theoretical and an experimental result. -
Compound-Nucleus Model
Bohr's formulated Compound-nucleus model explained nuclear reactions as a two-stage process. First the bombarding particle becomes an integral part of a new, highly excited, unstable nucleus, called a compound nucleus. The compound nucleus then loses its energy in different ways, such as losing a neutron or emitting gamma rays. The model is successful in explaining nuclear reactions induced by relatively low-energy bombarding particles. -
Discovery of Fission
Bohr and John Archibald Wheeler develop the liquid drop model in nuclear physics to explain the mechanism of fission. In the model, the structure of nucleus was like a liquid drop of incomprehensible liquid. Like a drop could be deformed from its basic spherical shape to form two new drops, a large atomic nucleus, like uranium, could fall apart to form two new atomic nuclei. The liquid drop model was a ground-breaking work to explain nuclear fission theoretically. -
Debates with Albert Einstein
Albert Einstein and Niels Bohr were involved in a series of public debates about quantum mechanics. These debates are considered important to the philosophy of science. They represented one of the highest points of scientific research in the first half of the twentieth century and also brought to focus quantum non-locality, which is absolutely essential in our modern understanding of the physical world. It is generally believed that Bohr proved victorious in his defense of quantum theory. -
An Open Letter to the United Nations
After the war, things unfortunately went as Niels Bohr had predicted: An arms race between the United States and the Soviet Union began. In 1950, he wrote An Open Letter To the United Nations. It contained an appeal for greater openness in the world as the way to cooperation and the prevention of catastrophic consequences of technological development.https://www.youtube.com/watch?v=3mSPLm48qcQ
